The present invention relates to a fluorescent lamp fixture for mounting a ballast and at least one fluorescent lamp. Fluorescent lamp fixtures are used in a variety of settings including residential, commercial, and industrial buildings. The fluorescent lamps mounted in such fixtures provide light in an energy efficient manner. In general, fluorescent lamps are gas-discharged lamps that use electricity to excite mercury atoms in a gas-filled tube. The excited mercury atoms emit short-wave ultraviolet light, which in turn causes a phosphor coating on the lamp to fluoresce thereby producing visible light. Fluorescent lamp fixtures often initially cost more than incandescent lamp fixtures because fluorescent lamp fixtures require a ballast. The ballast is used to regulate the current flowing through the lamp. Without a ballast to control the current, the fluorescent lamp will blow out. The ballast can also provide the striking voltage required to light the lamp. The life of a ballast is affected by heat. If the ballast is exposed to high temperatures for an extended period of time, it will degrade. Some fluorescent light fixtures known in the art provide a shield or other insulating material to isolate the ballast away from the heat emitted from the fluorescent lamp. Ballasts are typically rated for use at a maximum case temperature of 85° C.-90° C.
At one time it was standard practice to construct a fluorescent lamp fixture housing out of metal. It was also known that heat dissipation was promoted by connecting the ballast directly to the metal housing. In recent years, housings molded from a resinous material have become popular and offer cost advantages, weight savings, and durability. The practice of mounting the ballast directly to the housing was discontinued with the molded housings because the heat from the ballast could deform the resinous material and jeopardize the integrity of the connection between the ballast and the housing. Instead, the standard practice with molded housings has been to mount the ballast spaced from the housing so that there is an air space between the two. Surprisingly, with the present invention the use of a metal strip inserted into a groove in the housing and used to mount the ballast to the housing has been found to offer several advantages.
First, by mounting the ballast directly to the metal strip, heat dissipation is promoted—resulting in a lower temperature within the housing when compared to the prior art construction where the ballast is mounted spaced from the housing.
Second, the metal strip, which is sandwiched between the ballast and the housing, precludes damage to the molded housing from the heat of the ballast.
Third, use of the metal strip provides a secure attachment point for the ballast so that in the event of excessive heat, such as upon ballast failure, the connector for the ballast remains structurally intact and precludes failure at the attachment point, which would not be the case if the ballast was affixed directly to the molded housing.
Fourth, the use of the metal strip facilitates attachment of the ballast without t drilling holes in the housing which is labor intensive and could negatively impact the structural integrity of the housing.
Fifth, the utilization of the metal strip provides for an unlimited number of positions along the length of the housing where the ballast may be mounted, which is not possible when holes are drilled in the housing or predrilled holes are utilized.